Editing Juglans (section)

===Fruit===
The fruits of the walnut are a type of [[accessory fruit]] known as a pseudodrupe (or drupe-like nut), the outer covering of the fruit is an [[involucral bract|involucre]] - in a drupe the covering would be derived from the carpel.<ref>{{Cite book|page=250|title=The Encyclopedia of Seeds: Science, Technology and Uses|author1=J. Derek Bewley |author2=Michael Black |author3=Peter Halmer |publisher=CABI|date=2006|isbn=9780851997230}}</ref>

====Nuts and kernels====
[[File:Walnuts by RustedStrings.jpg|thumb|Persian walnut (''Juglans regia'') seeds]]

The nut kernels of all the species are edible, but the walnuts most commonly traded are from the ''J.&nbsp;regia'', the only species which has a large nut and thin shell. ''J.&nbsp;nigra'' kernels are also produced commercially in the US.

Two-thirds of the world export market{{citation needed|date=July 2015}}{{how|date=July 2015}}<ref>{{cite web|url=http://www.fas.usda.gov/htp/Hort_Circular/2004/12-10-04/12-04%20Walnuts.pdf |title=Walnuts |work=[[USDA]] |access-date=2015-07-16 |url-status=dead |archive-url=https://web.archive.org/web/20121018232341/http://www.fas.usda.gov/htp/Hort_Circular/2004/12-10-04/12-04%20Walnuts.pdf |archive-date=October 18, 2012 }}</ref><ref name="walnuts.org">{{cite web |url=http://www.walnuts.org/walnuts101/history_cultivation_processing.php |title= California Walnut History, Cultivation & Processing &#124; California Walnuts|website=www.walnuts.org |archive-url=https://web.archive.org/web/20090803161811/http://www.walnuts.org/walnuts101/history_cultivation_processing.php |archive-date=August 3, 2009}}</ref> and 99% of US walnuts are grown in California's [[Central Valley (California)|Central Valley]] and in Coastal Valleys, from [[Redding, California|Redding]] in the north to [[Bakersfield]] in the south.<ref>{{cite web |url=http://www.walnuts.org/walnuts101/faq.php |title= Frequently Asked Questions &#124; California Walnuts|website=www.walnuts.org |archive-url=https://web.archive.org/web/20090826070300/http://www.walnuts.org/walnuts101/faq.php |archive-date=August 26, 2009}}</ref>  Of the more than 30 varieties of ''J.&nbsp;regia'' grown there, Chandler and Hartley account for over half of total production.<ref name="walnuts.org"/> In California commercial production, the Hinds' black walnut (''J.&nbsp;hindsii'') and the hybrid between ''J.&nbsp;hindsii'' and ''J.&nbsp;regia'', ''Juglans x paradox'', are widely used as [[rootstock]]s for ''J.&nbsp;regia'' cultivars because of their resistance to [[Phytophthora]] and to a very limited degree, the oak root fungus.  However, trees grafted on these rootstocks often succumb to black line.<ref>{{cite web |url=http://www.padil.gov.au/viewPestDiagnosticImages.aspx?id=601 |title= |website=www.padil.gov.au |archive-url=https://web.archive.org/web/20120906054734/http://www.padil.gov.au/viewPestDiagnosticImages.aspx?id=601 |archive-date=September 6, 2012}}</ref>

In some countries, immature nuts in their husks are preserved in [[vinegar]]. In the UK, these are called [[pickled walnuts]] and this is one of the major uses for fresh nuts from the small scale plantings. In [[Armenian cuisine]], unripe walnuts, including husks, are preserved in sugar syrup and eaten whole. In Italy, [[liqueur]]s called [[Nocino]] and [[Nocello]] are flavoured with walnuts, while ''Salsa di Noci'' (walnut sauce) is a pasta sauce originating from [[Liguria]]. In [[Georgian cuisine|Georgia]], walnuts are ground with other ingredients to make [[walnut sauce]].

[[File:Green leaves of a walnut tree with budding walnuts.jpg|thumb|Green leaves of a walnut tree with budding walnuts, in [[Kashmir Valley]].]]

Walnuts are heavily used in India. In [[Jammu]], it is used widely as a ''prasad'' (offering) to Mother Goddess Vaisnav [[Devi]] and, generally, as a dry food in the season of festivals such as [[Diwali]].

The nuts are rich in [[Walnut oil|oil]], and are widely eaten both fresh and in [[cookery]]. Walnut oil is expensive and consequently is used sparingly; most often in [[salad dressing]]s.  Walnut oil has been used in [[oil paint]], as an effective binding medium, known for its clear, glossy consistency and nontoxicity.

Manos and Stone studied the composition of seed oils from several species of the [[Rhoipteleaceae]] and [[Juglandaceae]] and found the nut oils were generally more unsaturated from species which grow in the [[Temperateness|temperate]] zones and more saturated for species which grow in the [[Tropics|tropical]] zones.<ref>Manos, Paul S. and Stone, Donald E.: "Phylogeny and Systematics of the Juglandaceae" ''Annals of the Missouri Botanical Garden'' '''88'''(2)231–269 Spring, 2001</ref>  In the northerly-growing section ''Trachycaryon'', ''J.&nbsp;cinerea'' oil was reported to contain 15% [[Alpha-Linolenic acid|linolenate]] (the report did not specify whether the linolenate was the alpha (n-3) or gamma (n-6) isomer, or perhaps a mixture), 2% of saturated [[palmitic acid|palmitate]], and a maximum concentration of 71% [[linoleic acid|linoleate]].  In the section ''Juglans'', ''J.&nbsp;regia'' nut oil was found to contain from 10% to 11% linolenate, 6% to 7% palmitate, and a maximum concentration of  linoleate (62% to 68%).  In the section ''Cardiocaryon'', the nut oils of ''J.&nbsp;ailantifolia'' and ''J.&nbsp;mandshurica'' were reported to contain (respectively) 7% and 5% of linolenate, 2% of palmitate, and maximum concentrations of 74% and 79% linoleate.  Within the section ''Rhysocaryon'', the nut oils of the  U.S. native black walnuts ''J.&nbsp;microcarpa'' and ''J.&nbsp;nigra'' were reported to contain (respectively) 7% and 3% linolenate, 4% and 3% palmitate, and 70% and 69% linoleate.  The remaining results for black walnuts were: ''J.&nbsp;australis'' contained 2% linolenate, 7% palmitate, and 61% linoleate; ''J.&nbsp;boliviana'' contained 4% linolenate, 4% palmitate, and 70% linoleate; ''J.&nbsp;hirsuta'' contained 2% linolenate, 5% palmitate, and 75% linoleate; ''J.&nbsp;mollis'' contained 0% linolenate, 5% palmitate, 46% linoleate, and 49% [[oleic acid|oleate]]; ''J.&nbsp;neotropica'' contained 3% linolenate, 5% palmitate, and 50% linoleate; and  ''J.&nbsp;olanchana'' contained only a trace of linolenate, 9% palmitate, and 73% linoleate;

====Shells====
[[File:Walnuts.JPG|thumb|left|The shells of walnuts]]

The walnut shell has a wide variety of uses. Eastern black walnut (''J.&nbsp;nigra'') shell is the hardest of the walnut shells, and therefore has the highest resistance to breakdown. 
;Cleansing and polishing
:Walnut shells are mostly used to clean soft metals, fiberglass, plastics, wood and stone. This environmentally friendly and recyclable soft grit abrasive is well suited for air blasting, deburring, descaling, and polishing operations because of its elasticity and resilience. Uses include cleaning automobile and jet engines, electronic circuit boards, and paint and graffiti removal. For example: In the early days of jet transportation, crushed walnut shells were used to scour the compressor airfoils clean, but when engines with air cooled vanes and blades in the turbine started being manufactured, this practice was stopped because the crushed shells tended to plug up the cooling passages to the turbine, resulting in turbine failures due to overheating.
;Oil well drilling
: The shell is used widely in oil well drilling for lost circulation material in making and maintaining seals in fracture zones and unconsolidated formations.
;Flour
: Flour from walnut shells can be used in thermoplastic starch composites to substitute oil derivatives.<ref>{{cite web | url=https://bioresources.cnr.ncsu.edu/resources/physical-and-mechanical-properties-of-walnut-shell-flour-filled-thermoplastic-starch-composites/ | title=Physical and mechanical properties of walnut shell flour-filled thermoplastic starch composites :: BioResources }}</ref>
;Paint thickener
: Walnut shells are added to paint to give it a thicker consistency for "plaster effect" ranges.
;Explosives
: Used as a filler in dynamite.
;Cosmetic cleaner
: Occasionally used in soap and exfoliating cleansers.

====Husks====
[[Image:Walnut hand stain.jpg|thumb|upright|Staining from handling walnuts with [[husk]]s]]

Walnut husks are often used to create a rich yellow-brown to dark brown [[dye]] used for dyeing [[textile|fabric]], yarn or [[wood]] and for other purposes.  The dye does not require a [[mordant]] and will readily stain the hand if picked without gloves.